On Performance of Backscatter-NOMA Systems: Symbiotic Communication for IoT Devices

Backscatter communication and non-orthogonal multiple access (NOMA) are emerging paradigms in wireless communication offering promising solutions to enhance spectral and energy efficiency of energy-constrained devices in 6G networks. This work introduces a symbiotic radio system tailored for Internet of Things (IoT) devices and proposes an innovative framework that integrates backscatter-based IoT devices into the NOMA network. In this proposed system, the primary base station employs NOMA principles to serve both far and near users simultaneously. The IoT network consists of an IoT device equipped with a backscattering device that transmits its information over the primary signal, fostering a symbiotic relationship between the two. The IoT transmitter not only serves the IoT receiver but also concurrently enhances performance of the far user. This paper delves into an extensive analysis of the outage probabilities for the NOMA and IoT networks. The outage probability of the far user is obtained for the cases with and without a direct link between the primary base station and the far user. The obtained results clearly demonstrate a significant performance improvement over orthogonal multiple access techniques. Finally, we employ Monte Carlo simulations to validate the accuracy of the derived theoretical analysis.